how to rename a filename- starting at a certain track number

Hello - I am new to mp3tag. To this point it is a very useful tool!!

I have a question - I am trying to rename a bunch of filenames, starting with a certain track number.

Example: I have a filenames like this:
01 - desperado
02 - life is good
03 - where are you

I would like to renumber the tracks, starting at 12, so it looks like:
12 - desperado
13 - life is good
14 - where are you

When I go to Tag - Filename, I managed to manipulate the code to a certain point, but I get stuck how to put the code in to start the renaming at a certain track number.

I have this for code:
$num(%track%,2) - %title%

How do I add the code to have the track start renumbering at 12??

Any help would be appreciated

To me this looks a lot like the filename.
What about the field TRACK?
Do you want to add 10 to that, too?
Then use the numbering wizard and enter 11 as starting value.

If you have not yet filled the tags, use the filename as source with the function
Convert>Filename - Tag
Format string: %dummy% - %title%

After that, create new filenames with the function
Format string: $num(%track%,2) - %title%

Fiddling about with the just filename (and not the tag fields) is a little more complicated.